Add unit tests for Storage and HybridStorage

Author: vadymmarkov

Source/Shared/Library/ObservationToken.swift

@@ -1,11 +1,11 @@
-final class ObservationToken {
+public final class ObservationToken {
   private let cancellationClosure: () -> Void
 
   init(cancellationClosure: @escaping () -> Void) {
     self.cancellationClosure = cancellationClosure
   }
 
-  func cancel() {
+  public func cancel() {
     cancellationClosure()
   }
 }

Source/Shared/Storage/HybridStorage.swift

@@ -1,11 +1,10 @@
 import Foundation
 
 /// Use both memory and disk storage. Try on memory first.
-public final class HybridStorage<T>: StoreObservable {
+public final class HybridStorage<T> {
   public let memoryStorage: MemoryStorage<T>
   public let diskStorage: DiskStorage<T>
-
-  var observations = [UUID : (HybridStorage<T>, StoreChange) -> Void]()
+  public let registry = StorageObservationRegister<HybridStorage>()
 
   public init(memoryStorage: MemoryStorage<T>, diskStorage: DiskStorage<T>) {
     self.memoryStorage = memoryStorage
@@ -28,25 +27,25 @@ extension HybridStorage: StorageAware {
   public func removeObject(forKey key: String) throws {
     memoryStorage.removeObject(forKey: key)
     try diskStorage.removeObject(forKey: key)
-    notifyObservers(of: .singleDeletion)
+    registry.notifyObservers(about: .singleDeletion, in: self)
   }
 
   public func setObject(_ object: T, forKey key: String, expiry: Expiry? = nil) throws {
     memoryStorage.setObject(object, forKey: key, expiry: expiry)
     try diskStorage.setObject(object, forKey: key, expiry: expiry)
-    notifyObservers(of: .addition)
+    registry.notifyObservers(about: .addition, in: self)
   }
 
   public func removeAll() throws {
     memoryStorage.removeAll()
     try diskStorage.removeAll()
-    notifyObservers(of: .allDeletion)
+    registry.notifyObservers(about: .allDeletion, in: self)
   }
 
   public func removeExpiredObjects() throws {
     memoryStorage.removeExpiredObjects()
     try diskStorage.removeExpiredObjects()
-    notifyObservers(of: .expiredDeletion)
+    registry.notifyObservers(about: .expiredDeletion, in: self)
   }
 }
 

Source/Shared/Storage/Storage.swift

@@ -3,12 +3,12 @@ import Dispatch
 
 /// Manage storage. Use memory storage if specified.
 /// Synchronous by default. Use `async` for asynchronous operations.
-public final class Storage<T>: StoreObservable {
+public final class Storage<T> {
   /// Used for sync operations
   let syncStorage: SyncStorage<T>
   let asyncStorage: AsyncStorage<T>
 
-  var observations = [UUID : (Storage, StoreChange) -> Void]()
+  public let registry = StorageObservationRegister<Storage>()
 
   /// Initialize storage with configuration options.
   ///
@@ -48,14 +48,15 @@ public final class Storage<T>: StoreObservable {
 
   private func subscribeToChanges() {
     subscribeToChanges(in: syncStorage.innerStorage)
-    if syncStorage !== asyncStorage {
+    if syncStorage.innerStorage !== asyncStorage.innerStorage {
       subscribeToChanges(in: asyncStorage.innerStorage)
     }
   }
 
   private func subscribeToChanges(in storage: HybridStorage<T>) {
-    storage.observeChanges { [weak self] _, change in
-      self?.notifyObservers(of: change)
+    storage.registry.register { [weak self] _, change in
+      guard let strongSelf = self else { return }
+      self?.registry.notifyObservers(about: change, in: strongSelf)
     }
   }
 }

Source/Shared/Storage/StoreChange.swift

@@ -1,4 +1,4 @@
-public enum StoreChange {
+public enum StorageChange {
   case addition
   case singleDeletion
   case allDeletion

Source/Shared/Storage/StoreObservable.swift

@@ -1,26 +1,30 @@
 import Foundation
 
-protocol StoreObservable: class {
-  var observations: [UUID : (Self, StoreChange) -> Void] { get set }
-}
+public final class StorageObservationRegister<T: StorageAware> {
+  public typealias Observation = (T, StorageChange) -> Void
+  private(set) var observations = [UUID: Observation]()
 
-extension StoreObservable {
   @discardableResult
-  public func observeChanges(using closure: @escaping (Self, StoreChange) -> Void) -> ObservationToken {
+  public func register(observation: @escaping Observation) -> ObservationToken {
     let id = UUID()
-    observations[id] = closure
+    observations[id] = observation
 
     return ObservationToken { [weak self] in
       self?.observations.removeValue(forKey: id)
     }
   }
 
-  func notifyObservers(of change: StoreChange) {
-    observations.values.forEach { [weak self] closure in
-      guard let strongSelf = self else {
-        return
-      }
-      closure(strongSelf, change)
+  public func deregister(token: ObservationToken) {
+    token.cancel()
+  }
+
+  public func deregisterAll() {
+    observations.removeAll()
+  }
+
+  func notifyObservers(about change: StorageChange, in storage: T) {
+    observations.values.forEach { closure in
+      closure(storage, change)
     }
   }
 }

Tests/iOS/Tests/Storage/HybridStorageTests.swift

@@ -156,4 +156,20 @@ final class HybridStorageTests: XCTestCase {
       XCTAssertNotNil(try? storage.object(forKey: key2))
     }
   }
+
+  func testRegisterObservations() throws {
+    var changes = [StorageChange]()
+
+    storage.registry.register { storage, change in
+      changes.append(change)
+    }
+
+    try storage.setObject(testObject, forKey: "user1")
+    try storage.setObject(testObject, forKey: "user2")
+    try storage.removeObject(forKey: "user1")
+    try storage.removeExpiredObjects()
+    try storage.removeAll()
+
+    XCTAssertEqual(changes, [.addition, .addition, .singleDeletion, .expiredDeletion, .allDeletion])
+  }
 }

Tests/iOS/Tests/Storage/StorageTests.swift

@@ -1,5 +1,5 @@
 import XCTest
-import Cache
+@testable import Cache
 
 final class StorageTests: XCTestCase {
   private var storage: Storage<User>!
@@ -97,7 +97,19 @@ final class StorageTests: XCTestCase {
     XCTAssertEqual(cachedObject.firstName, "John")
   }
 
-  func testObserveAddition() {
-    
+  func testRegisterObservations() throws {
+    var changes = [StorageChange]()
+
+    storage.registry.register { storage, change in
+      changes.append(change)
+    }
+
+    try storage.setObject(user, forKey: "user1")
+    try storage.setObject(user, forKey: "user2")
+    try storage.removeObject(forKey: "user1")
+    try storage.removeExpiredObjects()
+    try storage.removeAll()
+
+    XCTAssertEqual(changes, [.addition, .addition, .singleDeletion, .expiredDeletion, .allDeletion])
   }
 }